The present invention relates to semiconductors, and more specifically, to vertical transport field effect transistors (FET) with precise gate length definition.
A metal-oxide-semiconductor field-effect transistor (MOSFET) is a transistor used for amplifying or switching electronic signals. The MOSFET has a source, a drain, and a metal oxide gate electrode. The metal gate is electrically insulated from the main semiconductor n-channel or p-channel by a thin layer of insulating material, for example, silicon dioxide or glass, which makes the input resistance of the MOSFET relatively high. The gate voltage controls whether the path from drain to source is an open circuit (“off”) or a resistive path (“on”). A fin type field effect transistor (FET) is a type of MOSFET. FinFET devices include an arrangement of fins disposed on a substrate. The fins are formed from a semiconductor material. A gate stack is arranged over the fins and defines a channel region of the fins, while regions of the fins extending outwardly from the channel region define active source and drain regions of the device. Various state-of-the-art techniques may be used for forming the fin.
One type of finFET is a vertical finFET. A vertical finFET operates like a normal finFET that is horizontal. However, the source and drain regions are positioned vertically with respect to the fin such that the current runs vertically from source to drain. Also, the gate usually wraps around the fin.